View
220
Download
0
Category
Preview:
Citation preview
INTRODUCTION
A new type of Unleaded Gasoline (Petrol) with
a minimum octane (RON) of 95 has been
introduced onto the Ghanaian market by a
major OMC (Oil Marketing Company) in 2007.
OBJECTIVE
Quality Control Dept. (TOR) tasked itself to
investigate if it is NECESSARY to produce 95
octane petrol.
APPROACH
Samples of OMC Petrol were obtained from
various filling stations
Properties where compared with the current
Premium Gasoline (Petrol) marketed by TOR.
Table 1. COMPARATIVE ASSAY OF OMCS AND TOR PREMIUM GASOLINE
TestSAMPLE GSB
LimitsOMC Premium TOR Premium
Density, kg/m3 746,0 764,4 725 - 790
RVP, kg/cm2 0,52 0,43 0,65 max.
Total sulphur, %wt 0,023 0,022 0,15max.
R. O. N. 97,8 91,4 91 min.
Copper corrosion 1a 1a 1b max.
Lead (TEL), %wt 0,000064 0,000034 0,013 max.
Test
SAMPLE
GSB LimitsOMC Premium TOR Premium
Distillation, ºC
IBP 33 40 Report
10% 50 60 70 max.
50% 96 120 120 max.
90% 153 185 190 max.
EBP 182 222 225 max.
TABLE 1 Continuation
TestSAMPLE
GSB LimitsOMC Premium TOR Premium
Composition, %vol.
Iso-Paraffins (Alkanes) 41,5 30,8
N-Paraffins (Alkanes)8,4 12,9
Olefins (Alkenes) 22,3 22,5
Naphthenes 5,6 9,2
Aromatics 22,2 24,6
TABLE 1 Continuation
Test
SAMPLE
GSB LimitsOMC Premium TOR Premium
Manganese (MMT), %wt 0,000003 13.6 < 0,001
Iron (Ferrocene), %wt < 0,01 < 0,01 < 0,01
Colour, commercial Green Red
Exist. Gum, mg/100 ml 3 3 5 max.
TABLE 1 Continuation
FINDINGS
OMC Petrol indeed has a minimum Octane
of 95.
The major difference is in the octane levels.
All other parameters were within our
National Specifications.
COMMON MISCONCEPTION IS THAT POWER
OUTPUT OR FUEL MILEAGE CAN BE
IMPROVED BY BURNING HIGHER OCTANE
FUEL THAN A PARTICULAR ENGINE WAS
DESIGNED FOR
OCTANE RATING MISCONCEPTION
Engine power is a function of the fuel as
well a the engine design and is related to the
octane rating of the fuel
PETROL DEFINITIONS
Research Octane Number (RON) or OctaneRating, is a measure of how resistant petrol is topremature detonation (knocking).
R.O.N is determined by running the fuel undervariable compression ratio, relative to amixture of isooctane and n-heptane.
Isooctane , 2,2,4 – Trimethylpentane burns verysmoothly in internal combustion engines and hasoctane rating of 100.
H3C C
CH3
C CH2
CH3
CH3
CH3
n-heptane
2,2,4 – Trimethylpentane
[CH3(CH2)5CH3 ]
n-Heptane produces much knocking when it is burnt in internal combustion engines and has an octane rating of 0%
PETROL DEFINITIONS
Octane rating does not relate to the energy
content of fuel, but, only a measure of the fuel’s
tendency to burn rather than to explode
A mixture of 87% (by volume) isooctane and
13% (by volume) n-heptane.
87-0CTANE RATING
COMPRESSION RATIO:
Basically it is the measurement of how much
the fuel/air mixture is compressed when the
piston reaches the top of its travel
PETROL DEFINITIONS
A compression ratio of 8 : 1 means that the
volume of fuel/air mixture compressed to
1/8th of its volume when the piston
reaches the top of its travel.
COMPRESSION RATIO
COMPRESSION RATIO OCTANE REQUIREMENT
5 : 1 72
6 : 1 81
7 : 1 87
8 : 1 92
9 : 1 96
10 :1 100
11 : 1 104
12 : 1 108
CORRELATION BETWEEN THE COMPRESSION RATIO AND THE OCTANE REQUIREMENT
The power output of an engine depends inpart on the energy density of its fuel.Switching to a higher octane fuel does notadd any more hydrocarbon content oroxygen, the engine cannot produce morepower.
Burning fuel with a lower octane rating thanrequired by the engine often reduces poweroutput and the efficiency one way or another.
CONCLUSION
POWER OUTPUT OR FUEL MILEAGE CANNOT
BE IMPROVED BY BURNING HIGHER OCTANE
FUEL THAN A PARTICULAR ENGINE WAS
DESIGNED FOR
Technically, TOR has the capacity to
produce high octane Petrol both on a
short term and long term basis.
POSSIBILITIES OF TOR PRODUCING HIGHER OCTANE FUEL
The RFCC Naphtha has an octane of about 94.0.
Addition of an octane booster such as MMT at a
dosage of 18 mg/l increases the octane to 96.
SHORT TERM SOLUTION
Petroleum Product Octane Number Quantity (MT)
RFCC Naphtha 94.0 111,354
Light Naphtha 74.0 67,614
Imported Petrol 93.0 235,433
GASOLINE POOL AT TOR
Chemical processes that results in high octane products
REFORMING
ALKYLATION
ISOMERISATION
LONG TERM SOLUTION
Rearrangement of molecular structures in
Heavy Naphtha to produce high octane
Reformate.
REFORMING
Combination of low molecular weight
alkenes such as propylene and butylenes
with isobutene to produce high octane
isomers called alkylates.
ALKYLATION
Rearrangement of straight chain C7
molecules in light naphtha into branched
isomers that have high octane.
ISOMERISATION
Recommended